also: やりとも
noun
fuck buddy; friend with benefits
Vulgar slang for a friend with whom one has a purely sexual relationship, without romantic commitment.
彼は恋人じゃなくて、ただのヤリ友だよ。
He's not my boyfriend, just a fuck buddy.
ヤリ友関係は割り切
A fuck-buddy relationship is easy because we keep it strictly physical.
恋人 implies a romantic partner, while ヤリ友 is purely sexual.
Compound of ヤリ (from 遣る, 'to do' in the sexual sense) and 友 (とも, 'friend').